Bench Test Results: Molicel P45B - 50A 4500mAh 21700…an incredible cell

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Electron Wrangler
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May 13, 2015
    These tests below only note my personal ESTIMATED ratings for the batteries I tested at the time I tested them. Any battery that is not a genuine Samsung, Sony, Murata, LG, Panasonic, Molicel, or Sanyo can change at any time! This is one of the hazards of using “rewrapped” or batteries from other manufacturers so carefully research any battery you are considering using before purchasing.

    Misusing or mishandling lithium-ion batteries can pose a SERIOUS RISK of property damage, personal injury, or even death. They should never be used outside of a fully protected battery pack and you use them at your own risk. Never exceed the battery’s true continuous discharge rating (CDR), never let it get colder than 0°C or hotter than 60°C, and keep the plastic wrap and top insulating ring in perfect condition. Never use a battery that is physically damaged in any way.

    Testing batteries at their limits is dangerous and should never be attempted by anyone who has not thoroughly studied the dangers involved, understands the risks, has the proper equipment, and takes all appropriate safety precautions.

    If the battery has only one current rating number, or if it only says "max", then I have to assume the battery is rated at that current level for any type of discharge, including continuous.

    52E0ACE0-B90C-4486-9FE0-55B2CE10F044.jpeg 03A0D45A-C0FD-42B4-866C-5DCD3BA9A168.jpeg 1509592F-18F5-422A-A5DF-17DFF308659D.jpeg C5055850-1D15-4693-A7C9-3883AF29C2A4.jpeg

    Test Results
    I tested these cells in January for my Patreon supporters and have been torture testing them along with the Molicel P42A and the Samsung 40T since then. With the release of the Molicel P45B hopefully coming soon it’s finally time to post some test results. The cycle life torture test results will remain patron-only though.

    The Molicel P45B is an extraordinary cell, matching or outperforming almost every other round cell I have tested at all current levels. The official word is that it will be available before the end of the year but there have been a couple of rumors that some vendors will have it by Summer. I can’t predict who will have it or when.

    Compared to the Molicel P42A, the P45B is supposed to have about 7% more capacity, 22% lower DC internal resistance (DC IR), and a higher charge rate. Its main competitor is supposed to be the Samsung 50S.

    In my testing the P45B was a better performer in every way over the Molicel P42A:
    • The P45B had almost 9% higher capacity.
    • The P45B had about 33% lower DC IR (at 100% charge).
    • The P45B’s charge rates are 4.5A standard/13.5A max (70°C cutoff) and the P42A’s are 4.2A standard/8.4A max (60°C cutoff).
    • The P45B had longer run times at all discharge current levels.
    The P42A is still a great cell! It’s just that in the four years or so we’ve been using it battery tech has improved and the P45B is a perfect example of that.

    Compared to the Samsung 50S…
    • The P45B has about 7%-8% less run time at 5A and 10A.
    • The P45B runs for longer though at about 15A and higher.
    • The P45B has a 26% lower DC IR (at 100% charge).
    • The P45B runs MUCH cooler at moderate to high current levels.
    • The P45B has a higher standard and max charge rating (2.5A/6A for the Samsung 50S).
    So while the Samsung 50S had slightly longer run times at 10A or lower, due to its higher capacity, the Molicel P45B beats it in every other way in my opinion. The P45B will easily be my choice for best all-around performing round cell and also my #1 choice for moderate to high power applications.

    The preliminary datasheet only lists a “temperature-limited” rating of 50A. Molicel says you can run this cell at 50A but only if it never reaches a temperature of 80°C (hot!).

    You cannot run the P45B at 50A continuously until it is empty! This non-continuous rating is set by Molicel for this cell’s intended applications; power tools, electric vacuum cleaners, and similar devices where the cell is used really hard for short periods of time.

    While you can run this cell at 50A for a while I recommend staying below about 35A to help reduce voltage sag, improve performance, extend cell life, and reduce risk. Especially if the cells are in a battery pack where they heat each other up. Use a 35A rating for comparing this cell to other cells with true continuous current ratings.

    The two cells I tested delivered 4477mAh and 4488mAh. This is great consistency and is typical of cells from the big manufacturers. The cells I tested exceeded Molicel’s 4400mAh minimum capacity rating but didn’t quite meet the 4500mAh “typical” rating. I’m not worried about this at all, especially since it’s only a tiny difference and I tested these cells in January and tweaks to the capacity can be made. I’ll retest these cells once they become widely available.

    See the table below for the delivered energy (Wh) and max temperatures the P45B, P42A, and 50S reached in testing.

    See my 21700 Ratings and E-Scores table (link below) to see how this cell performed against others.

    Four cells were sent to me for testing by N-Power Energy, global distributors for Molicels (Home – N-Power Energy Limited). Thank you!

    18650 Ratings and E-Scores Table:
    18650 Battery Ratings Table | E-Cigarette Forum

    20700/21700 Ratings and E-Scores Table:
    20700/21700 Battery Ratings | E-Cigarette Forum

    Delivered Energy (Wh) and Max Temperatures:

    Continuous Current Discharge Graphs:

    Ratings and Performance Specs Graphic

    I want to work for the community full time! If you feel what I do is worth a couple dollars a month and you would like early access to battery availability, battery testing and news, and a say in what I test, then please consider becoming a patron and supporting my testing efforts: Battery Mooch is creating battery and device tests | Patreon.

    To see how other cells have tested check out this link: List of Battery Tests | E-Cigarette Forum
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